Filament reinforcing means for rubber articles



Sept. 19, 1950 L. w. MITCHELL FILAMENT REINFORCING MEANS FOR RUBBER ARTICLES Filed March 20, 1950 EI- XT-ISycEEI Sm IN! 'm'roie. LEE W MITCHELL z/ alawa P ATTORNEYS belts and more particularly to novel Patented Sept. 19, 1950 ,FILADIENT REINFORCING MEANS FOR RUBBER ARTICLES Lee W. Mitchell, Denver, Colo., assignor to The Gates Rubber Company, Denver, 0010., a corporation of Colorado Application March 20, 1950, Serial No. 150,657

2 Claims. (Cl. 74-232) 1 This invention relates to power transmission reinforcing means for same.

One of the objects of the invention is to provide reinforcing means for use in power transmission belts, which may act in tension or compression, the reinforcing means being formed of a plurality of parallel disposed bonded filaments.

Still further objects, advantages, and salient features will become more apparent from a consideration of the description to follow, the appended claims, and the accompanying drawing.

in which:

i ure 1 is a diagrammatic isometric view of apparatus for fabricating the reinforcing mate}- rial;

Figure 2 is an enlarged section and isometric view taken on line 2-2. Fi re 1;

Figure 3 is a section taken on line 3-3, Figure 1; I

Figure 4 is a section taken on line 4-4, Figure 1;

Figure 5 is a side elevation of another form of apparatus for fabricating the reinforcing material;

Figure 6 is a section taken on line 66, Figure Figure 74s a side elevation of a further form of apparatus for fabricating the reinforcing material;

Figure 8 is'a section and isometric view of a piece of flexible material incorporating the reinforcing material formed by any of the apparatus disclosed; and

Figure 9 is a similar view showing the application of the invention to a power transmission belt.

Referring in detail to the drawing, and particularly Figures 1 to 4, a plurality of tubes or rolls III, forming a creel I I, are rotatably mounted on suitable pintles l2, these tubes containing zero twist yarns I3 of multiple filaments II, that is, the filaments in each yarn all lie parallel to each other as shown in Figure 2. The rolls may be tensioned in any way well-known in the art. The yarns are guided through slits I5 of reed-like member I6, the upper set I'I passing around stationary rods I8, [8a and the lower set I9 around rods 20, 20a. These rods reorient the filaments of the yarns so that the filaments are disposed in substantially planar relationship, as shown in Figure 3. The flattened yarns then pass around rods 2 I, 2i a which lays them into a sheet of filaments as shown in Figure 4. The sheet of filaments then passes between spray pipes 22, 23 which apply a settable agglutinant thereto. They may then pass through an air drier or oven 24, emerging therefrom as a finished sheet R of bonded filaments which may be readily handled in the fabrication of articles of manufacture.

Figure 5 illustrates a single yarn I30 passing 2 around stationary rods I80, I8I|a which flatten the filaments as before described. They are then fed onto adrum 25 in adjacent layers, as shown in Figure 6. They are then sprayed with a settable agglutinant by spray pipe I22, and when the agglutinant has set are removed from the drum and are ready for use.

Figure 7 illustrates another manner in which a yarn may be flattened and spread. the yarn 230 passing over a brush wheel 26 which has a peripheral velocity greater than the velocity of the yarns. This device may be employed in lieu of rods I80, I80a of Figure 5. If employed in lieu of rods I8, I8a, 20, 20a of Figure 1. it would merely be lengthened to engage any desired number of yarns fed thereover.

Synthetic artificial filaments which have been found satisfactory include the following: Viscose rayon which is regenerated cellulose, a linear polymer consisting of glucose anhydride units linked through the 1 and 4 atoms by a betaglucoside linkage; acetate rayon which is produced by reacting cellulose with acetic anhydride in the presence of acetic acid; textile nylon which is a synthetic linear polymer, produced by the reaction of hexamethylene diamine with 3 adipic acid, the molecule being entirely aliphatic and based on the formation of polyamides; Orlon, formerly known as "Fiber A, which is produced by polymerization of monomeric acrylonitrile under the influence of catalysts; Fiber V which is produced by reaction of terephthalic acid and ethylene glycol; and Fortisan," which is produced by orienting and saponifying acetate rayon. All Of these filaments have the common characteristic that they are extruded in any continuous length, as distinguished from short natural fibers.

The agglutinants may vary and include natural latex, dispersed reclaim, polychloroprene (neoprene), butadiene vinyl pyridine (BAC) and butadiene styrene (GRS), any of the foregoing being dissolved by resorcinol formaldehyde, isocyanates or proteins.

When the reinforcing material R is incorporated in a rubber article, such as article 21. Figure 8, the article is built up in the usual manner and the sheet or strip of bonded filaments R is disposed therein in the same manner as twisted cords or other reinforcing material such as woven fabric formerly employed, a twisted cord being understood in the art as a cord which is constructed from plied yarns having filaments disposed spirally therein, the yarns also being spirally disposed in the cord. After vulcanizing, the filaments become bonded to the article.

Some articles require reinforcing means which are subjected to tension and compression. Figure 8 illustrates an article of this type,'subjected The reinforcing material has many advantages over twisted cords which have, prior to this invention, been extensively used. If, for example,

a twisted cord material is employed as a tension section, each cord has a considerable thickness or diameter which does not permit all filaments of the cord to be subjected to pure tension when the tension section is in fiexure. the filaments of the twisted cord elongate during tension they unduly stretch because they are helically disposed rather than parallel. Also, there is internal work between the filaments which causes premature fatigue. With the present invention, the individual filaments all lie in a thin compact sheet and each filament is in pure or substantially pure tension, there is considerably less stretch, no substantial loss due to internal work between filaments and marked increased resistance to fatigue. For example, the useful lives and power ratings of power transmission belts using the disclosed filaments disposed in parallel relation, as compared with the same number of filaments disposed in relationships formerly employed, such as in cord form, have been found to be materially increased. It will also be apparent that in the foregoing comparison, the actual .volume of filament material for the same lengths of reinforcing material is also less with this invention than in a construction wherein the cords are formed of filaments in twisted relationship. Other advantages are confinement of high tensile strength to a very thin cross section, uniformity of load distribution in the filaments, maximum utilization of tensile characteristics of the filaments, higher strength per unit of volume of filaments, and concentration of strength in a thinner layer due to reduction of size of interstices between filaments. It will be apparent that the same advantages prevail where the filament material is used in compression.

Figure 9 illustrates a V-belt i2! wherein the tension section is composed of a layer of the reinforcing material R. Belts so constructed have been found to have longer life and higher power ratings than belts reinforced with cords or woven fabric having a comparable number of filaments. The material is also ideally adapted for reinforcing thin belts which operate at very high speeds around small pulleys, such as employed on abrasive high speed grinders, since they can be constructed thinner and lighter, and hence are more fiexible without sacrifice of strength, their lightness reducing loss of traction which results from centrifugal force.-

It is immaterial to the invention, in its broadest aspects, how the filaments are treated or manipulated to place them in final bonded relationship in a sheet adapted to be employed as the reinforcing for the article of manufacture. Thus, I have disclosed in the drawing, methods of first disposing the filaments in parallel relationship, and then applying the settable agglutinant thereto. It is apparent, however, that the method steps may be reversed, that is, the agglutinant may be applied to a yarn of filaments and the yarn thereafter flattened to dispose the filaments in a thin sheet. The yarns having zero twist therein have been chosen to illustrate the invention, but it is to be understood that the filaments may be disposed in parallel relation in any manner other than from yarns of filaments. The filaments which have Moreover, as

been found particularly useful for the purpose range from denier 1 through 20, the diameter of nylon denier No. 1 being .00044 of an inch and denier No. 20 being .00196 of an inch. The diameters of the same deniers in rayon filaments are 87 of the values given the lower limit thus being .00038 of an inch. It is apparent, therefore, that these filaments are very small as compared to socalled monofils such as employed for fishing lines and leaders, etc. It is apparent, also, that working with filaments of such small diameter there is bound to be some overlaying or crossing of the filaments at various points. The filaments do, however, lie substantially parallel to their adjacent filaments and in substantially abutting relationship thereto and the language of the claims is to be construed to cover such construction even though there may be some crossing of filaments at various points. The number of superposed filaments in the sheet may vary, the sheet being perhaps 25 to 30 filaments thick where the filaments are of very small diameter. The sheet, however,

will still be very thin as compared to twisted cords formerly employed. The Width of the sheet of filaments may vary as desired, depending upon the width required for a reinforcing section. The term sheet, therefore, is to be construed in its broadest and most generic sense as including a narrow thin ribbon-like reinforcing section or a wide thin section. In some instances it may be desirable to apply the unbonded filaments directly to the article in a thin flat sheet and subsequently effect bonding of the filaments together.

Having described the invention, what I claim as new is:

1. An endless power transmission belt having a rubber-like body and a tension section therewithin extending longitudinally thereabout, said section comprising a thin prefabricated sheet having a plurality of extruded synthetic artificial filaments not greater than .002 inch in diameter and not less than .00038 inch in diameter, the filaments being disposed in substantially parallel relation and adjacent filaments being in substantially abutting relationship and bonded together during preiabrication of the sheet by a settable rubber-like liquid agglutinant, the sheet with the set agglutinant thereon being juxtaposed to the body and bonded thereto by vulcanization of the body, vulcanization effecting a bond between the agglutinant and the material of the body.

2. An endless power transmission belt having a rubber-like body and a tension section therewithin extending longitudinally thereabout, said section comprising a thin sheet having a plurality of extruded synthetic artificial filaments not greater than .002 inch in diameter and not less than .00038 inch in diameter, the filaments being disposed in substantially parallel relation and adjacent filaments being in substantially abutting relationship, said filaments and body being bonded together by vulcanization.

LEE W. MITCHELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,294,821 Yelm Sept. 1, 1942 2,331,323 Jahant Oct. 12, 1943 2,411,027 Crosby Nov. 12, 1946 2,441,071 Jahant May 4, 1948 2,494,810 Bacon et al. Oct. 18. 1949 

